In late 2018 my trailer was blowing the truck's fuse for the wire that goes to the right brake/turn signal. After some diagnosis I found that the heavy connecting cable that runs from the pin box to the truck's connector was pinched and had a short between the ground and the right brake/turn signal. I temporarily spliced the frayed wires and eventually replaced the connecting cable.
2013 Silverado 2500HD LTZ CC 6.6L Duramax Diesel
2014 Sunset Trail SF270BH
Holly & Buster, mini Dachshunds
2016: 1 trip, 3 nights in 1 state, 316 miles
2015: 5 trips, 18 nights in 3 states, 2707 miles
2014: 5 trips, 14 nights in 3 states, 2426 miles